This invention relates to a portable electronic apparatus so-called as an IC card which contains an IC chip provided with a writable/rewritable non-volatile memory and a control element such as a CPU and having means for executing input/output of external data.
In recent years, an IC card containing an IC chip having a non-volatile data memory as a portable data storage medium and a control element such as a CPU (central processing unit) for controlling the non-volatile data memory has attracted a great deal of attention.
In such a type of IC card, a data memory is divided into a plurality of files, and each of the files stores data necessary for using the application program. The IC card having such a constitution selectively enables only a corresponding file to be used with use of an application identifier or the like supplied from an external apparatus. With this constitution, a plurality of application data can be used for various objects by dividing it into files, and storing then in an IC card.
In the above-mentioned conventional IC card, however, the data memory contained therein is divided into a plurality of files, and the data necessary for using an application program is stored apart in the files, and thus the reading, correcting, adding, and deleting operations of the data string stored in these files and the data writing operation are complicated and difficult to be executed.